Acquiring And Preparing Lead For Cast Bullets

     Do not try to use the lead from any batteries, they contain poisonous materials. NO BATTERIES!!!

     We get lead for casting bullets from various sources. Here are some, in increasing order of expense.

     Range scrap can be picked up free on the backstop, and is easily cleaned.

     Used wheel weights are available from tire centers and garages for little or no money. There are some ZINC wheel weights out there. You don't want to have any zinc in your alloy. These zinc wheel weights look different from the lead ones, and melt at a much higher temperature. You may see them floating on top of the melted alloy. Pick them off and throw them away. Bring a container with you when scouting the tire centers; a sheet rock joint compound bucket works well.

     Lead pipe and flashing can be found sometimes. Make friends with plumbers and roofers.

     Scrap dealers almost always have wheel weights for sale, and sometimes have linotype or other type metals such as foundry type or monotype.

     There are at least two mail order sources for cast bullet alloys as this is written. (2007)

     I get a bucket of wheel weights and melt them down in my lead pot outdoors. Put in the wheel weights, let them melt, scrape the clips off the top of the pot, flux a lot with a candle, scrape the pot sides with the dipper and clean all the bad stuff off the top of the melt. Then pour the alloy into a 12-muffin muffin tin with the dipper to make 12 ingots. A 10-pound Lee pot holds enough alloy to make 12 substantial ingots. Pile these ingots together. Then put more wheel weights in the pot, remove clips, flux, scrape and pour another 12 ingots and put them in a second pile. Continue this until all the wheel weights are gone, or until there are 12 piles of ingots.

     Now, let's say that there are 8 piles of ingots, 12 ingots per pile. Put one ingot from each pile in the pot, melt, flux, and pour 8 ingots in the muffin pan. Then put these ingots into their own special pile. Continue this until all the ingots are re-melted and re-poured. The result in the example is 8 X 12 = 96 ingots that are quite homogeneous; bullets cast from this lot of 96 ingots will be of the same weight and hardness.

     This takes a lot of elapsed time, but the process doesn't require constant attention. I do other things while the wheel weights melt.

     For harder alloys I make up a pot full using the wheel weight ingots and linotype or foundry type.

     I used to have a plumber's "Bomb", a propane melting apparatus with a pot holding about 100 pounds of metal. The bomb was fast, but a little scary. It was loud, and a bit unstable. I gave it away. I don't like to use tools that I'm afraid of.

Lead Alloys And Bullet Hardness

     Lead alloys and the bullets cast from them vary in hardness. As more tin and antimony are added the bullets get harder. Hardness is measured on the Brinell scale; measurements are in “Brinell Hardness Numbers” or BHN. Cast bullets are made from various alloys of lead, tin, antimony, and arsenic.

     Most bullets are cast of wheel weights. Additional alloying metals can be added to wheel weights; we are told that the addition of tin makes casting easier and helps the mold fill out and make bullets without lines or wrinkles. I cast most of my bullets from straight wheel weights with no problems with lines or wrinkles on the bullets.

     For pistols at velocities below about 1000-1300 fps and rifles at velocities below about 1600-1800 fps, wheel weight bullets are fine. For higher velocities, the bullets may need to be harder.

     This table is the result of an Internet search. Note that there are different percentages and hardness’s associated with some alloys. (Hardness can be influenced rather sharply by age, heat treatment and minor contaminants like arsenic, and other trace metals that usually aren’t even listed as ingredients.) I am skeptical of any digits to the right of the decimal place unless the alloy is made in a laboratory. These alloys will probably vary by at least +/- 1 BHN in practice.

     In 2006 we conducted a BHN test of wheel weight alloy, performed by eight shooters using LBT, Lee and SAECO testers. This test suggests that 2005 wheel weights have a BHN of ~12.

     The addition of more than 10% tin to lead does not increase the hardness of the alloy much. Most of the hardness from tin is obtained with the first 5%. 

     The addition of antimony does increase hardness in proportion.

     There is some arsenic in most lead alloys. Arsenic seems to be important in the heat-treating of bullets. Arsenic is essential to increasing hardness by heat treating and quenching as it provides the needed “interlocking of the lead and antimony crystalline structures” – ask a metallurgist for a better explanation.

     Wheel weights are cheap and easy to find and work well for casting most pistol bullets and rifle bullets.

     If harder bullets are required, linotype can be used. Linotype metal is easy to find, is about $1 per pound in 2006, and is hard enough for rifle bullets up to a reported 2300 fps and sometime more.

     Heat-treating or "quenching" bullets cast of wheel weights will increase their hardness. Heat-treating cast bullets to increase hardness is not necessary for most shooting, and is best left to the more advanced caster and reloader. For an excellent explanation of these processes, see "Bullet Quenching" and "Heat Treating Cast Lead Bullets".

     This graph is from "Type Metal Alloys" By Frances D. Weaver, B.Sc. (Mrs. Harold Haywood), see: Journal of the Institute of Metals, Vol. LVI, 1935. The graph has been edited.

     The two graphs below show various lead-tin and lead-antimony alloys and their reported BHNs. The sources were "Cast Bullets" by E. H. Harrison, and several internet sites. Note the variation in the BHN’s, and that pure lead is reported to have a BHN of 4 in some sources, 4.2 and 5 in others.

     Based on all of this data, I conclude that the BHN of any lead-tin or lead-antimony or lead-tin-antimony alloy probably varies depending on, at least, how the sample(s) were taken and the sample time-since-molten; and that BHN precision to one decimal point, or maybe even to one ones digit, is questionable.

     Based on all of this data, I conclude that the BHN of any lead-tin or lead-antimony or lead-tin-antimony alloy probably varies depending on, at least, how the sample(s) were taken and the sample time-since-molten; and that BHN precision to one decimal point, or maybe even to one ones digit, is questionable.

A Cheap way to test lead alloy hardness

James Carter

I was reading a book from the late 50's at a friend's home that was put out by the NRA on how to test lead hardness on the cheap. I gave it a whirl and it works great so I thought I would share for those of you who are cheap like I am.

You need about 2 pounds or so of pure lead, your test lead and a steel ball bearing and a vise and a set of calipers/micrometer and that is it.

     To get the pure lead you can find it in a metal supply shop but it runs about 3-4 bucks a pound or you can save the stick on weights when you find them in your bucket of wheel weights. I bought a couple of pounds to see what the difference was between it and the stick on version and the BHN number is about 5.2 or 5.3 instead of the 5 for pure lead, so close enough.

     Drop by a bearing shop and pick up a 1" steel ball bearing and that costs about 2 bucks or so.

     Melt the pure lead(stick on weights)in a muffin tin and your test lead in the one muffin slot next to it. I waited a day to test because I am anal that way.

     Pad the vise with aluminum or steel on the jaws so that the lead doesn't dig into the teeth of the jaws. Hold up the lead in one jaw and the test lead on the other jaw and slowly squeeze the two together with the ball bearing in the middle. Just squeeze till there is a good dent on both surfaces of the lead or about 1/5 or the way in on both sides of the ball bearing.

     Here is the formula BHN= 5 X (lead dia./test dia.)^2

     With the calipers measure the diameter of the indent in each of the leads and plug in the values.

     I had some WW and an unknown lead from a Radiator shop that I wanted to test and here are the results.

• Diameter in Lead=0.479

• Diameter in WW=0.325

     So 5 x (0.479/0.325)^2 and that gives 10.8 BHN where it should be for air cooled Wheel Weights. 

     I had my friend test the WW on his Lee Hardness tester and he came up with 11, so close enough.

• Unknown lead from radiator shop

• Dia. in Lead=0.520

• Dia. in Unknown=0.279

• So 5 x (0.520/0.279)^2 which gives us 17.4 BHN

     I knew it was harder just with the old thumb nail test but I had no idea it was that hard.

     Again on the Lee it came back as 17 BHN. So this is a great cheap way to test lots of lead, it won't work so good on single bullets like the expensive models but at least you know what the raw materials BHN number is approximately.

A Simple Method Of Measuring Alloy Hardness

David Berry

     This describes a method for the determination of lead alloy hardness. It is a simple, quick, and economical means to test hardness of unknown alloys, and I have found it to be reliable and accurate. 

     Using a common staple gun, I have found that measuring the penetration of the staple into the alloy can be used to determine relative hardness when compared to a series of "standard" known lead alloys. I simply inject a staple into the sample and measure the post of the staple that protrudes. I obtain 5 readings on each known standard, average them and prepare a calibration chart versus known BHN values. A sample chart is shown below. Unknowns are then subjected to the same procedure and the resulting measurements are compared on the chart to determine relative hardness.

5 readings for each alloy in inches

Arrow T-50 stapler

3/8" staples

     I first started working on 1 pound ingots of the same size, but found that size or shape is not all that important, the sample just needs to be large enough to hold the staple gun onto it. I apply about 20 pounds of pressure on each sample (determined with a bathroom scale) while I inject the staple. I have used a Bostich electric staple gun and this works well also. A 3/8 inch staple is about the largest that can be used as longer staples deform. This can be overcome by measuring the actual penetration by subtracting the protrusion as measured above, from the total length of the staple post.

     Each staple gun must of course be calibrated as will the batch of staples being used.

     I find this to be an extremely easy method to determine alloy hardness, and by measuring several samples have determined it to be very reliable and fairly accurate. It works very well on odd sample shapes and sizes. 

Identifying tin

Dan Hudson asked if there was an easy method of identifying tin.

     Willis Gregory: "Cast samples of KNOWN tin and the mystery metal in the same mould
(bigger is better here!). Compare weights, diameters/lengths and the hardness as you did before. Can also do specific gravity easily at home- ratio of weight in air to weight in water. With really good thermometer temperature of melting/freezing is 450 degrees F."

    Ric Bowman: "If you have an accurate way to measure the temperature, melting point
is about 449.47 degrees F. If it is less than this it most likely is linotype. If greater it has some amount of lead."

     Bill McGraw: "Tin (Sn) has a specific gravity (SG) of 7.298 gm/cc compared to lead (Pb) at 11.34 gm/cc or about 64% of lead. If using WW alloy of about 11 gm/cc and a bullet weighs 175 gr, the tin bullet will weigh only 116 gr (66%). Tin also has a slightly yellow color compared to lead and WW alloys, but the cast weight is one simple method to try. The melting point of 450F is another way but takes longer to use. Weights of bullets can tell you much of what elements are present, although there is some guesswork involved since antimony’s (Sb) SG, 6.62, is similar to tin’s and would be nearly impossible to melt in a furnace and dangerous to try. The as cast BHN is the number I use for most references compared with soft lead scrap (6-7 BHN), linotype, foundry type, and others. The heat-treat and quench BHN also tells if arsenic (As) is included as a trace element. A BHN tool is a good investment yet I can get along without one if needed as side cutting pliers will tell of approximate hardness simply by cutting sample bullets: soft alloys will cut clean; WW will cut clean and fracture slightly near the middle of the bullet; and HT-Q alloys will fracture nearly at the cut. Besides using the LBT tool for BHNs, I use the cutting method to verify the hardness of annealed noses and the approximate point where the harder shank is located."

     Frank Washam: "Lead and lead alloys will mark [like a pencil] on paper. Tin will not mark  A pure tin ingot sometimes has a bronze color cast to it. Other than checking the melting point and specific gravity these are about all the tests I know available to the average bullet caster."

     Don Loops: "A trick a scrap metal dealer taught me years ago is to bend the bar near your ear. Tin will "crackle" as it is bent. (You might need to make a smaller strip by melting and pouring it on a flat surface.) It also has a somewhat slightly yellowish tint to it as I recall." (This "crackle" is sometimes called "tin cry"-once you hear it you won't forget it. Ed.)

     The Pencil Test For Lead Alloy Hardness

Ken Mollohan

     The pencil industry manufactures what are called 'art pencils' for draftsmen, artists, etc. They are available as either conventional wood sheathed graphitic cores, or as a mechanical pencil for which you only buy the graphitic cores and insert them as desired.

     The hardness of art pencils is controlled very strictly, and they are designated by a letter-number combination. The scale runs from at less than 6B (VERY soft) and gets slightly harder with each step up, going to 5B, 4B, 3B, 2B, B, HB, H, 2H, 3H, 4H, 5H, 6H, 7H, 9H, 10H, 11H and 12H that I know of. 6B is softer that most scrap lead, while 12H will cut into some grades of aluminum and copper, which are far harder than most lead alloys.

     This provides 18 steps in hardness, but you won't need much more than about the range of 6B to about 2H. Oh yes, there ARE even softer and harder art pencils, but they're not often used, and can be pretty hard to find. 

     They are used industrially to measure the hardness of paints, among other things. I have a background in the paint industry, and have used the technique for my alloys for decades. It's really quick, simple, easy, and reproducible from one time to the next, and from one person to the next.

     To use them to measure hardness properly does take a certain technique, but it's easy to learn:

     You prepare the pencil by peeling away the wood sheath (or simply advancing the replaceable core in the mechanical version) to leave a cylindrical graphitic core. It's best to do this with your fingernails to avoid scraping the core if you want to get the best (most consistent) results.

     Now hold the pencil straight up and down as you smooth the tip on a bit of fine sandpaper. I usually use something like 360 to 400 grit. The objective is to form a perfectly square sharp wadcutter configuration on the end of the pencil core, so that you can reproduce the exact same cutting edge every time. Blow a puff of air on the tip or wipe it very gently with a bit of cotton to remove any loose graphite.

     Now hold the pencil at a 45 degree angle to the surface of the lead, and push along the length (the long axis) of the pencil. If the sharp edge of the core is harder than the lead, it will dig in and scratch the surface. If the core is NOT harder than the lead, the sharp edge will crumble, and it will skid across the surface of the lead.

     You should be aware of a couple of easily avoided problems that can mess up your results:

1. You need to move to a new spot on the lead for each test. Otherwise, the next pencil core could skid more easily on the surface, which is now lubricated with graphite from the previous test.

2. Likewise, the pencil should be rotated slightly for the each test: Skidding across the lead surface will blunt the sharp edge, and unless you rotate the pencil in your fingers to present a fresh cutting edge, the blunted edge will not cut in as well.

3. These graphite cores were not originally designed for this test, as I mentioned above. Mixing of the clays, graphite, etc is not always perfect, and you may occasionally (!!) encounter a tiny pinpoint of grit that will give you a false indication. For this reason, you need to make several tests with the same pencil, rotating it for a fresh edge each time. You can easily get three or four tests from the same tip before it needs to be re-sharpened. If it gouges on one test, but slips on the others, assume the one gouge was due to a pinpoint hard speck, and rate it as equal to the majority results.  It's not a real problem, just something to be aware of.

     Hardness is rated as being equal to the hardest pencil that will NOT cut into the surface. For example, if a 'HB' pencil skids across the surface, but a 'H' pencil makes gouges, your alloy is 'HB' in hardness.

     One of the nice things about this technique is the very small area needed to test. Once you have the knack, you can easily get meaningful results on loaded ammo, sprues, or most any surface that gives you a uniform surface about an eighth of an inch long for each pencil.

     Hope you find this interesting and useful. Feel free to ask any questions that may occur to you. Ken Mollohan

How And Why To Measure Alloy Specific Gravity

     Cast bullet shooters are sometimes interested in the composition and hardness of bullet alloys. Precise assays of these alloys are expensive, and individual shooters seldom want to know enough to pay for the test. Hardness of bullet alloys can be measured with hardness testers that are available from LBT, Saeco and Lee.

     I don't have a hardness tester, and have used the Specific Gravity of alloys to estimate the composition and hardness of those alloys. This isn't precise, but it's close enough for me.

     My records of weights of 311299 bullets shows the weight varying from an average of 208.8 grains (wheel weights) down to 197.8 grains (wheel weights with foundry type added). This is a difference of about 5% in weight and specific gravity, and this difference of 5% is a great difference in percentage of tin or antimony and in hardness. Keeping track of weights of bullets in different alloys is one way to estimate the hardness of the alloy. Measuring the specific gravity is another.

     The Specific Gravity of a material is the ratio of that material's density to the density of water. If a quart of material K weighs twice as much as a quart of water, the Specific Gravity of material K is 2. If a cubic inch of metal L weighs eleven times as much as a cubic inch of water, the Specific Gravity of metal L is 11. For lead-tin-antimony alloys, as the specific gravity goes down the hardness goes up. If there are other metals such as gold or silver or zinc or arsenic or cadmium or copper, we'll never know by calculating the Specific Gravity; but if it casts good bullets it probably doesn't have much of anything exotic in the alloy.

 Specific Gravity

    Weight of sample (bullet) in air minus Weight of sample in water equals Weight of the water displaced by the sample.

     Weight of sample (bullet) in air divided by Weight of the water displaced by the sample Equals  Specific Gravity of the sample.

     To measure the Specific gravity of an alloy we need a sample of the alloy-a bullet works fine, a scale, a glass, some water and a piece of thread.

     Here's the scale up in the air with a bullet suspended by a thread from the pan holder. Just hanging there. The bullet with thread weighs 434.5 grains.

     Here's the bullet in a glass of water, not touching the sides or bottom of the glass. Just hanging there. The bullet and thread weighs 395.6 grains in the water.

     To make an informed guess as to the composition of that sample alloy we'll use this table that shows the Specific Gravity for some possible alloys of lead, tin and antimony. For an explanation see the EXCEL workbook "leadtinantimonyharmonicmean.xls" in Appendix.

     Note that a Specific Gravity of 11.17 occurs with: (see bold red entries) several combinations of tin, lead and antimony.

     Thanks to "LINSTRUM" and Tom Myers on the Cast Boolits forum for pointing out that the harmonic mean was the proper measure of alloy S.G.So the mystery alloy has about 2% to 3% of (probably) tin and/or antimony.

     See the table above in LEAD ALLOYS AND BULLET HARDNESS.

     For about 3% of the mystery alloy being (probably) tin and/or antimony, there are several choices from the table. Either wheel weight opinion is at BHN of 9 or a 40-1 Lead-Tin at BHN 8 to 8.5.

     My informed guess is that the BHN is about 8 to9.

     For my purposes this estimating technique is precise enough. After all, it's about shooting cast bullets, not Materials Science 101.

     Note: At small percentages of tin and antimony in the alloy, the mathematical calculations used to prepare the tin/antimony % table may overstate the Specific Gravity of an alloy by 1 to 2 percent. Since the estimation of the constituents of the alloy is an approximation or an informed guess, this possible error is not considered significant.